I use warm water and a couple drops of SuperClean, which is an automotive de-greaser. Soap should have the same effect, especially dish-washing liquid, and that is to remove grease or oil, like mold release compounds and skin oil from handling the pieces. But when I first tried using SC, to remove the chrome from a sprue of chromed parts, I noticed that the parts were left literally squeaky-clean, and I realized that the solution completely removed the chrome and left the bare plastic. I started using SC in place of dish-washing liquid...edit... At eight bucks a gallon, for something that can be used over and over, it's a bargain. Prost! Brad